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Jeff mc

4rt running rough

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1 hour ago, Jeff mc said:

Ok. May be worth checking then. I can't see them being that far off but I'll see. I guess it would be more of an issue if the clearance is not enough. That would mean the valves aren't closing fully wouldn't it.  

Both sides to tight or loose can see similar symptoms depending on what the clearance is and witch valve is in question.  I don't remember off the top of my head what symptoms are directly connected to witch valve being in what condition but I have seen almost everything in the range on my old 74 beetle from tight to loose on both sides.  

Edited by jonnyc21
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Would just do tank first - then try injector but never heard of one .

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Failing fuel pump will alllow you to ridd on low revs but can’t  cope with sudden or higher revs - but like a blocked jet .

i found got worse with time / heat .

if you stop bike it gets better fiir a while after.

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Have you by any chance plugged the lighting exstention into the main loom?

I did for MOT. It ran very similar to what you describe.  

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I'm not sure if it has a plug for lights. I did find a 2pin socket with a red blank cover over it but though that would be for plugging a computer in to. No lights on it anyway.   Thanks anyway though. 

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Heading out to check valve clearances now. I may back them off a bit to the upper end of the tolerances to make sure. 

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Right.... wait for it... I think I've fixed my bike thanks to your brilliant help- all of you.  Valve clearance was set a bit tight. Slackened to the max clearance. Put some Di electrical grease on the 32 pin connector. Put a 1mm shim on the max throttle stop in the throttle body. Fired it up and revved great. Flicked the 1mm shin off because I'd just used hot glue as temporary. This made the back fire come back. So. Tight valves weren't helping and perhaps I need a shim fixing permanently. Throttle position sensor is perhaps worn. Much better though and light at the end of the tunnel! 

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Not wanting to pick holes on a good news story but thought you had tried an alternative throttle body early on in your diagnosis .

just my engineering brain trying to putt :Peverything in its correct pigeon hole

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This is the new (second hand) theottlebody that I bought. I can only think that the position sensor in it is slightly worn too. I need to try my original one back on to fully see if it was the valves and Di electrical grease which worked. Like anything I should have changed one thing at a time but with limited time to tinker I changed as much as I could.  I'll report back what I find though as it's stuff like this that will help others. 👍🏻

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I tried the old throttle body back on and it was really poor. Bogging down at all revs when the throttle is opened quickly. So the newer throttle body is in now with a shim in and it seems really good. So possible causes contributing were valve clearance on the tight side, poor connection on the 32 pin ecu and also the injector connection- cured by Di electrical grease.  

 

Thanks. 

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